If adding funds by card results in an error together with a message, asking to contact your bank, this would mean that your card issuer is stopping the top-up request from going through.
This is relevant for both newly added and cards, with which you already managed to top-up successfully.
Such decline reason is most likely due to some restrictions placed on the card or your bank could be stopping the top-ups from going through to keep the bank account safe - because they do not recognize our service.
In these cases, please contact your bank's Cards Payment Division and let them know you authorize transactions to Revolut. It's also worth checking the settings in your online banking if there are any limits for online spending.
As a workaround, you can try topping up with a smaller amount, Apple/Google Pay, a bank transfer or a different card.